For when Moses had spoken every precept, &c.— Moses, in his account of the transaction, Leviticus 16 does not mention all the circumstances spoken of in this verse. St. Paul might very probably have received them from tradition. However, the apostle's account was confirmed by the inspiration of the Holy Spirit of God. Ceremonies of a similar kind are prescribed, Leviticus 14:4-6; Leviticus 14:49-52 as in cleansing the leper; and it is highly probable, that the sprinkling the blood of the sin-offering might be done in this method. The blood was mixed with water, to preserve it from coagulating; and perhaps to this the mixture of sacramental wine with water, which pretty soon prevailed in the primitive church, might have some intended reference. Owen is of opinion, that the ceremony here referred to, was constantly performed on the day of atonement: it is certain, however, that it is not expressly prescribed in the account given of the ritual of that day.
Related Commentaries of Hebrews 9:19
Hebrews 9:19
19 For when Moses had spoken every precept to all the people according to the law, he took the blood of calves and of goats, with water, and scarletg wool, and hyssop, and sprinkled both the book, and all the people,